The present invention relates generally to fluid delivery systems, to fluid delivery devices and to methods of fluid delivery, and, especially, to fluid delivery systems, devices and method for delivery of medical fluids to a patient.
In many medical procedures, such as drug delivery, it is desirable to inject a fluid into a patient. Likewise, numerous types of contrast media (often referred to simply as contrast) are injected into a patient for many diagnostic and therapeutic imaging procedures. For example, contrast media are used in diagnostic procedures such as X-ray procedures (including, for example, angiography, venography and urography), computed tomography (CT) scanning, magnetic resonance imaging (MRI), and ultrasonic imaging. Contrast media are also used during therapeutic procedures, including, for example, angioplasty and other interventional radiological procedures as well as chemotherapy. Saline is often used as a diluent or flushing fluid in conjunction with contrast media. Regardless of the type of procedure, any fluid injected into the patient must be sterile and contain a minimum of pyrogens. Moreover, injection of air should be minimized or completely eliminated.
Under the typical current practice of injecting contrast media via syringe pumping systems using loadable, empty syringes, hospitals must purchase and stock many contrast media concentrations in multiple container sizes in an attempt to provide the correct concentration and amount of a specific contrast for a specific procedure, while minimizing the wastage of contrast. In that regard, contrast is typically very expensive. Most contrast media are thus provided by manufacturers in numerous concentrations in sterilized containers (such as glass bottles or plastic packages) ranging, for example, incrementally in size from 20 ml to 500 ml (and even up to 1000 ml under current European practice). These containers are generally designed for a single use (that is, once a container is opened for a patient, it is used for that patient only). The contrast is generally aspirated from such containers via the syringe pump used to inject the contrast, and any contrast remaining in the container is discarded to prevent infection with potentially contaminated contrast. The hospital staff is faced with the task of choosing an appropriately sized contrast container to assure an optimum study while minimizing discarded contrast. Time consuming procedures are required to reload the syringe if more contrast is required than originally calculated. On the other hand, expensive waste results if only a portion of a filled syringe is injected. The inventory of contrast containers required under the current system increases costs and regulatory burdens throughout the contrast media supplier-consumer chain.
Alternatively, contrast is provided in prefilled syringes which can be loaded onto an injector without time-consuming filling procedures. However, such syringes are provided in single-dose volumes. The hospital must still maintain an inventory of disposable syringes of different volumes and concentration. Moreover, hospital staff is still required to choose a prefilled syringe of appropriate volume to ensure that sufficient contrast is available during the injection procedure. Waste occurs if the prefilled syringe includes excess fluid. Waste also occurs, for example, in the case that a prefilled syringe includes insufficient fluid, resulting in termination of a procedure or use of only a portion of a second prefilled syringe.
Many of the costs, regulatory burdens and other problems associated with the use of multiple contrast containers, and even prefilled syringes, can be substantially eliminated through use of relatively large contrast media containers for single- and multiple-patient use in connection with a pumping system allowing any volume and concentration (as limited by the volume and concentration of the medial container) of contrast to be injected as determined by the hospital staff before or during a procedure. Relatively large containers of a fluid such as saline can be used for flushing and/or dilution. U.S. Pat. Nos. 5,916,197 and 6,197,000, assigned to the assignee of the present invention, the disclosures of which are incorporated herein by reference, disclose pumping systems that are removably connectible to a relatively large source of contrast or saline. Those pumping systems are adapted to provide controlled, continuous flow of generally any volume of fluid during an injection procedure.
Although continuous pumping systems such as disclosed in U.S. Pat. Nos. 5,916,197 and 6,197,000 can eliminate many of the problems associated with current injection practices, a number of problems persist. For example, there is a risk of contamination by operating personnel when removable fluid connections are made or broken (such as the fluid connection between a fluid source and the pumping mechanism of the pumping system). Making such fluid connections also requires use of valuable and limited operator time. Furthermore, required operator tasks introduce the potential for human error.
It thus remains desirable to develop improved fluid delivery systems, fluid delivery devices and methods of fluid delivery.